document recurring billing start date

diff --git a/OnlinePayment.pm b/OnlinePayment.pm
index 64c66db..1426fc7 100644 (file)
--- a/OnlinePayment.pm
+++ b/OnlinePayment.pm
@@ -474,7 +474,7 @@ and units (currently "days" or "months" in either singular or plural form).
 =item * start
 
 The date of the first transaction (used for processors which allow delayed
-start).
+start) expressed as YYYY-MM-DD.
 
 =item * periods